Email->HTML Image

As per https://petervojtek.github.io/diy/2015/07/28/share-messages-with-kindle-on-fridge.html#comment-2277153819
If you don't want to use Google Apps Script, this could convert an email with an image URL in it's subject (you can also change that to the URL of the first attachment) to an appended HTML file. Until the file is less than 2MB (which is a lot for text) then the included JS code would allow only the final image to be displayed.
This is a quick and dirty hack, more elegant solutions are available